India, Dec. 6 -- IndiGo has been in the midst of an "operational crisis" - as termed by the airline - over the past few days, with well over 1,000 flight cancellations in a single day on Friday.

As the carrier struggled with getting its flights airborne, scenes of chaos unfolded across airports in the country, after cancellations hit major hubs including Delhi, Hyderabad and Bengaluru.

The airline, India's largest, has attributed the crisis to a "multitude of unforeseen operational challenges", also citing minor tech glitches, winter schedule changes and the weather.

However, aviation insiders and regulators have pinned the reason to be the implementation of Flight Duty Time Limitations (FDTL). The new duty-hour rules, brought in to en...